Roller bit



Nov. 5, .1929. Q H M, BULL 1,734,760 l ROLLER BIT v Filed Dec, 17, 1927 filllllllll:,\ I l INVENTOR.

BY j

A TTORNE Y.

Patented Nov. 5, 1929 l UNITED STATES OFFICE l CLINTON H. M. BULL, OFHOU'STON, TEXAS, ASSIGNOR TO REED ROLLER BIT COMPANY,

' OF HOUSTON, TEXAS, A CORPORATION OF TEXAS ROLLER BIT Application filed December 17, 1927. l Serial No. 240,670. Y

This invention relates to certain new and useful improvements in roller bits of the type covered by my Letters Patent of the United States No. 1647269, dated November 1, 1927.

It has for its general object to provide a new and improved roller cutterV mounting and assembly.

One of its specific objects is the provision, in a one-piece bit head having a recess in the bottom thereof, of new and improved means to removably mount in said recess a plurality of roller cutters arranged in a manner similar to that disclosed in my said Letters Patent.

Another specific object is to provide improved bearings for roller cutters.

A further object is to provide means to so mount the side roller cutters in the recess that the adjacent edges thereof define upwardly diverging lines, the teeth of the cutters being thus exposed to'the cleaning iiuid discharging into the recess.

Various other objects will hereinafter apear. p In the accompanying drawings, which are illustrative of the preferred embodiment of the invention, Fig. 1 is a fragmentary and artly sectional side elevation of the assembled bit; and F ig. 2 is a diagrammatic bottom lplan view.

Referring specifically to the drawings, the

bit has a one-piece head 1 with a cutter recess in the bottom thereof into which cleaning fluid is discharged from the slush course 2.

The lowermost side portions 3 of the head have frusto-conical bearing surfaces upon which the side roller cutters 6 are mounted, a bushing 6a being interposed therebetween. The lowermost edges of these bearing surfaces lie in a plane substantially at right angles to the longitudinal or vertical axis of the'head. The internal surface of each of the frusto-conical side cutters 6 is substantially parallel to the outer surface thereof. The cutters are, therefore, so mounted that their axes 'of rotation extend inwardly and downwardly, and the pressure thereupon is absorbed directly by the head.

The adjacent edges of the cutters 6 define upwardly diverging lines, so that slush issu-v the side cutters 6.

the annular Harige of nut 8. The bolt bore i 5 extends between said recesses downwardly and inwardly toward the longitudinal axis of the head. l

The nut- 8 is locked against rotation by its l diametric key 8a fitting in slots in the portion of the head indicated at 3, and in the bushing 6, this construction being very similar to that disclosed by my Letters Patent of the United States above referred .to. Y

The nuts 8 have substantially cylindrical pockets to house the cross roller cutters 7, which are mounted upon pin 9.

Slidable within each cylindrical bolt 9 is a pin 10 with a ball 10a on the end thereof fitting in the semi-spherical socketl in the adjacent end of cross roller cutter spindle 11. The spindle 11 is revoluble on balls 10a, and cutters 7 are revoluble on spindle 11, whereby wear is divided. The balls are held in proper positions with respect to spindle 11 by means of adjustable set-screws 12 in contact with the outer ends of pins 10.

The elements above described constitute removable bracing means for the head, serving toprevent objectionable inward movementof .The assembly of the parts may be effected by placing bushings 6a on the bearing surfaces of the head, cut-ters 6 on said bushings, nuts 8 within said cutters so that the keys thereof lit in the key slots, holding the cross roller cutters in the pockets in nuts 8, inserting bolts 9 with pins 10 therein, thru the bores 5, screwing bo1ts9 into nuts 8, and adjusting set-screws 12. 4 j

The parts may quickly and easily be separated after bolts 9 and pins 10 have been removed. v

The many advantages of the invention will be apparent to those skilled in theart.

The following claims are not limited t0 the specific embodiment above described, and various changes may be made With the scope thereof:

I claim:

1. In a rotary boring drill, a pair of cutter spindle supporting pins having balls on the ends thereof, a cutter spindle, and a roller cutter on said spindle, said spindle having `pockets in the ends thereof shaped to revolubly receive said balls.

2. In a rotary'boring drill, a head, a cutter on said head, a cylindrical bolt in said head and having a nut to hold said cutter on said head, a cutter spindle, a cutter on said spindle, and a pinv within said bolt and revolubly connected to one end of said spindle to support the same.

3. In a rotary boring drill, ahead having a recess in the bottom thereof and bores leading into said recess, oppositely disposed side roller cutters in said recess adjacent to said bores, bolts in said bores to hold said side roller cutters in place, means to hold said bolts in said bores, pins Within said bolts, a

spindle supported by said pins between said side roller cutters, and a cross roller cutter on said spindle.

4. In a rotary boring drill, a head having a recess in the bottom' thereof, and bores leading into said recess, oppositely disposed side roller cutters insaid recess adjacent said bores, bolts in said bores, means to hold said bolts in said bores, pins Within said bolts, a spindle revolubly supported by said pins between said side roller cutters, and a cross roller cutter on said spindle.

5. In a rotary boring drill, a head, a pair of downwardly converging pins on said head, each of said pins having a ball thereon, a spindle having a socket in each end thereof to revolubly receive one vof said balls, and a roller cutter on said spindle.

6. In a rotary boring drill, a head having a cutter recess and a bore communicating With said recess, a cutter spindle in said recess, a cutter on said spindle, a bolt in said bore, releasable means to hold said bolt in said bore, a pin in said bolt, said bolt and pin bein removable outwardly from said head, an said pin `being separably connected to one end of said spindle, and means to support the other end of said spindle. y y,

7. In a rotary boring drill, a head having a recess and a pair of bores communicating with said recess, bolts in said bores, releasable means to hold said bolts 1n said bores, pins .in said bolts, said bolts and pins being removable outwardly from said head, a cutter.

spindle in said recess and connected to said pins, and a cutter on said spindle.

8. In a rotary boring drill, a head having a recess and a pair of bores communicating with said recess, bolts in said bores, releasable means to hold said bolts in said bores, pins in said bolts and having balls thereon, said In testimony whereof, I hereunto affix my signature.

CLINTON H. M. BULL. 

